1. Field of the Invention
The present invention relates to a magneto-optical device which is highly transparent and capable of repeatedly carrying out recording and reading operations including erasing through magnetic heads. The magneto-optical device may also be used in a polarizer, in a display device for displaying picture images by applying a magnetic field and illuminating light, in a spatial optical modulator and in magnetic field sensor.
2. Description of the Related Art
When linearly polarized light is incident on a magnetized material with its propagation direction parallel to the direction of the magnetization of the magnetized material, the plane of the linear polarization is rotated by the magnetic field, which is well known as the Faraday effect. Utilizing magnetic materials having a relatively large coefficient of the effect, several devices have been fabricated such as magnetic recording media and spatial optical modulator.
As examples of such devices, there disclosed are magnetic recording media (1) using yttrium rare-earth iron garnet and its derivative disclosed in Japanese Laid-Open Patent Application 56-15125/1981, (2) using hexagonal ferrite in Japanese Laid-Open Patent Application 61-89605/1986, (3) a coated magnetic recording medium using yttrium iron garnet particulates in Japanese Laid-Open Patent Application 62-119758/1987 and (4) another coated magnetic recording medium using rare-earth iron garnet particulates in Japanese Laid-Open Patent Application 4-132029/1992.
These magnetic recording media each generally consist of thin layers of either magnetic material or its particulates disposed on a substrate.
Although these media in general have excellent capability of writing and reading various information data, their use has been rather limited to those applications mentioned above. In other words, they are not so advantageous for other applications such as, for example, information display.